James Carlson wrote:
> The problem is indicated above. open(9E) is almost always "active" on > a serial port, because there are threads there snoozing away, waiting > for someone to assert DCD. If that's the case, it's impossible to do this safely without locks. There's no way for the driver to guard against both threads being active at the same time. I believe that the framework must guarantee that there will only be a single thread active in the driver at a time for this to work they way they want it to work. In that case, if quiesce(9e) is active, even if DCD is asserted, that thread won't become active at the same time that the driver is in quiesce(9e) and there won't be two threads competing over the registers/resources of the device. -David
